Laser-Assisted Laterally Positioned Flap Operation: A Randomized Controlled Clinical Trial
For figures, tables and references we refer the reader to the original paper.
Introduction
During recent decades, several surgical procedures were proposed for correcting gingival recession
defects with varying degrees of success. These techniques include pedicle flaps [coronally advanced
flaps1 and laterally positioned flaps (LPF)],2 free soft tissue grafts,3 and combinations of these
procedures.
The LPF is primarily indicated for isolated recession defects on mandibular teeth.2,4 The tooth adjacent
to the recession defect serves as the donor site for a flap that has been moved laterally to cover the
recession defect.5 Previous studies reported a defect coverage ranging from 61% to 74% with a mean of
67% indicating partial success.5–10 The limitation of the technique to the sites with an adequate amount
of adjacent keratinized donor tissue and possible postoperative recession at the donor site were
considered to be the disadvantages of LPF.11,12
Currently, diode lasers are generally accepted and widely used as a tool for soft tissue
management.13,14 The energy level of diode laser is absorbed by pigmentation in the soft tissues,
making diode laser an excellent hemostatic agent for soft tissue surgeries.13 Other advantageous
properties of diode lasers are relative ease of ablation of tissues, little wound contraction, minimal
scarring, and less postoperative pain.14,15 Compared with a conventional scalpel, diode laser can cut,
ablate, and reshape the oral soft tissue more easily, with no or minimal bleeding and little pain requiring
no, or only a few, sutures.13–15 Therefore, in periodontal therapy, diode laser treatment may serve as a
good alternative, especially for the fine cutting of soft tissues such as depigmentation, gingivectomy,
gingivoplasty, and frenectomy.16
As it is important to achieve tension-free advanced flap for succesful clinical outcomes17,18 in routine
periodontal plastic surgery techniques, attempts have been made to reduce this tension. Therefore, the
purpose of the current clinical trial was to compare the effectiveness of a new treatment approach,
which consisted of an LPF procedure combined with an external vestibular releasing incision, versus LPF
alone, for the treatment of single gingival recession defects. In order to reduce the reported ecchymosis
and edema, the external vestibular releasing incision was made by a diode laser (laser-assisted laterally
positioned flap [LALPF]). The null hypothesis to be tested was that there would be no differences in
clinical and aesthetic parameters between LALPF and conventional LPF for the treatment of gingival
recession defects.
Material and Methods
This was a parallel, randomized, single-center, clinical trial. Isolated single Miller II gingival recession
associated with minimal loss of interdental papilla was included in this trial.19
Sample size
Sample size was calculated with the clinical parameter (gingival recession depth) estimate based on a a
previous article.18 Assuming a minimum clinically significant value (d) is 0.5 mm with a 0.46 standard
deviation for gingival recession depth, the minimum sample size was ∼16 in each study groups, within a
95% confidence interval and 80% power.
Patient selection
Thirty-two systemically healthy patients, 13 males and 19 females, ages 25–39 years, were enrolled in
the study. The participants of this study were chosen among individuals who were referred to the
Periodontology Department of Cukurova University between March 2011 and February 2012. The
approval of the Local Ethics Committee of Cukurova University Faculty of Dentistry was obtained (IRB2010-4-3). All participants were informed about the study and signed an informed consent form in
accordance with Helsinki Declaration principles.
Inclusion criteria
Miller class II deep and narrow isolated recession defects (≥5 mm in depth and ≤1.5 mm in width) with
minimal interdental papilla loss (distance between contact point and papilla tip ≤2 mm) on lower incisors
were included in this study (Fig. 1A–C). The inclusion criteria were: presence of identifiable
cementoenamel junction (CEJ); presence of a step ≤2 mm at CEJ level and/or the presence of a root
abrasion, but with an identifiable CEJ; a full-mouth plaque score of <10%;20 no occlusal interferences;
periodontal and systemic health; no contraindications for periodontal surgery; and not taking
medications known to interfere with periodontal tissue health or healing. All patients were nonsmokers.
Randomization
Patients were allocated to one of the two treatment groups using a computer-generated randomization
table. Sixteen patients were assigned to the test group (LALPF), and the other 16 patients were assigned
to the control group (LPF alone).
Initial therapy and clinic measurements
In both groups, a session of prophylaxis was performed, and coronally directed roll technique was
prescribed for teeth with recession to eliminate traumatic tooth brushing habit related to the etiology of
the recession.18,21 The criterion for surgery was optimal plaque control with a full mouth plaque score
of ≤10%.22 The gingival23 and plaque index24 were used to assess gingival health conditions throughout
the study.
At the baseline and 6 months after surgery, the following clinical parameters were recorded to the
nearest millimeter:3,25 (1) gingival recession depth (GRD), measured as the distance between the most
apical point of the CEJ and the gingival margin (GM); (2) gingival recession width (GRW), measured as the
distance between the mesial gingival margin and the distal gingival margin of the tooth (measurement
was recorded on a horizontal line tangenital at the CEJ); (3) probing depth (PD), measured as the
distance from the GM to the bottom of the gingival sulcus; (4) clinical attachment level (CAL), measured
as the distance from the CEJ to the bottom of the sulcus; (5) apicocoronal width of keratinized tissue
(KTW), measured as the distance from the mucogingival junction (MGJ) to the GM, with the MGJ location
determined using a visual method;25 (6) recession depth reduction; (7) mean root coverage (MRC); and
(8) complete root coverage (CRC). CRC was calculated according to the formula of Zucchelli et. al., and
the defects with a score of 100 were considered as completely covered.26
The measurements were performed using a UNC-15 periodontal probe.
Intraexaminer reproducibility
One examiner, who was blinded to the surgical procedures, performed the clinical measurements and
also assessed all patient related outcomes of treatments (M.C.H.). The examiner evaluated 20 patients
with Miller class II recession defects that were not involved in the study, on two occasions (24 h apart).
Calibration was accepted if 90% of these recordings could be reproduced within a difference ≤0.5 mm.27
Control group (LPF technique)
All surgical interventions in the test and control groups were performed by the same periodontist (E.Y.)
in order to prevent interoperator variations.
The LPF procedure used in the control group (Fig. 2A) was a modification of the surgical technique
described by Grupe.12,28 Briefly, a reverse bevel incision was made along the soft tissue margin of the
defect for the removal of the pocket epithelium. At ∼3 mm from the wound edge, which delineates the
defect at the side opposite the donor area, a superficial incision was made extending from the gingival
margin to a level ∼3 mm apical to the defect. Another superficial incision was placed horizontally from
this incision to the opposite wound edge. The epithelium and outer portion of the connective tissue
within the area were removed by sharp dissection. In this way, a recipient bed was created at the one
side of the defect. A tissue flap to cover the recession was then dissected in the adjacent donor area. The
preparation of this flap was initiated by a vertical superficial incision parallel to the wound edge of the
recession and at a distance, which exceeded the width of the recipient bed ∼3 mm. This incision was
extended beyond the apical level of the recipient bed and was terminated within the lining mucosa with
an oblique releasing incision directed toward the recession site. An incision connecting the vertical
incision and incision previously made around the recession were placed ∼3 mm apical to the gingival
margin of the donor site. A split thickness flap was then prepared by sharp dissection. Deepithelialization of the facial soft tissue of the interdental papilla was performed by scalpel. The
prepared tissue flap was rotated ∼90 degrees and sutured at the recipient bed.
Test group (LALPF technique)
The diode laser (810 nm) was applied first in the test group (Fig. 3A and B). An external horizontal
releasing incison on the vestibular alveolar mucousa was made with diode laser (3 W, continuous mode).
The laser incison was started ∼5 mm apically from the recession defect and extended superficially to the
distal of the donor teeth (Fig. 3C). This incision provided a very fine partial dissection of the mucousa
removing all tension from muscle and/or frenum attachments and at the same time preserving partial
blood supply to the flap. Then the recipient site and donor tissue were prepared, laterally positioned,
and sutured as in the control group (Fig. 3D–F) with the exception that de-epithelialization of the
interdental papilla was also performed by diode laser in the test group.
In both groups, the interrupted periosteal 5-0 sutures (Ethicon, Johnson & Johnson nylon monofilament)
were used for close adaptation of the pedicle graft to the underlying recipient bed. At the end of the
surgery, periodontal dressing was applied.
Postsurgical protocol
The patients were prescribed ibuprofen as needed. All patients were instructed to abstain from brushing
and flossing around the surgical area until suture removal. The sutures and periodontal dressing were
removed 7 days after surgery. Plaque control in the surgically treated area was maintained by
chlorhexidine (0.12%) rinsing for an additional 2 weeks (Fig. 3G and H).29 After this period, patients were
reinstructed in mechanical cleaning of the treated tooth. All patients were recalled once every 2 months,
until the final examination (Fig. 2B and Fig. 4A and B).21
Patient evaluation of postoperative condition and aesthetics
Data on perceived hardship of procedure was measured by VAS (VAS-H) (0 indicating easy to cope, 100
indicating difficult to cope) with scores from 0 to 100.30 The postoperative discomfort and aesthetics
were evaluated by the patients on a 100 mm VAS.20 The questionnaire was divided into two parts: the
first part, regarding the postoperative morbidity and pain, was completed 1 week after surgery (VAS-P)
(0 indicating very bad, 50 indicating average, and 100 indicating an excellent postoperative course), and
the second part, concerning patient satisfaction with the aesthetic outcome, was completed at the 6
month follow-up (VAS-E) (0 indicating very bad, 50 indicating average, and 100 indicating
excellent).20,31–34
Evaluation of clinical aesthetic outcomes
The aesthetic evaluation was performed according to the root coverage aesthetic score system (RES),
published by Cairo et al.35 Five variables were evaluated, which included; GM, marginal tissue contour
(MTC), soft tissue texture (STT), MGJ alignment, and gingival color (GC). Zero, 3, or 6 points were used
for the evaluation of the position of the GM, whereas a score of 0 or 1 point was used for each of the
other variables.
Statistical analysis
Data analysis was performed using SPSS software (version 19.0 for Windows; SPSS Inc, Chicago, IL).
Nonparametric tests were chosen for continuous variables, as the data were not distributed normally.
Comparisons between groups were applied by using the Mann–Whitney U test. Time dependent data
were analyzed by Wilcoxon's signed rank test. Differences (Δ) between baseline and the 6th month were
calculated. The categorical variables between the groups were analyzed by using the χ2 test. Results
were presented as mean±SD and median (min-max), n, and %. A p<0.05 was considered as significant.
Results
Sixteen patients were treated in each group. However, there was one dropout in the LPF group; this
patient could not comply with the study schedule. The data of the patient were not included in the
statistical analysis. Postoperative healing of patients was uneventful.
The baseline patient-related characteristics are summarized in Table 1. No statistical differences were
observed between groups for any measurements at baseline (Table 2). Statistically significant differences
of GRD, CAL, PD, and KTW between baseline and 6 months were observed within each group (p <
0.0001). The analysis of the mean differences of the clinical parameters between baseline and 6 months
(Δ) showed significant differences between groups for GRD, CAL, and KTW (p < 0.001, p < 0.018, p <
0.026, respectively) (Table 2).
Thirteen of the 16 defects in the LALPF group (81.2%) and 7 of the 15 defects (46.7%) in LPF group
exhibited CRC (Table 3). At the 6 month follow-up examination, the mean root coverage scores were
75.7% for the control group and 92.5% for the test group.
There was no difference of data from immediately after surgery on perceived hardship of procedure
between groups (VAS-H). VAS-P measurements between the treatment groups in the 1st postoperative
week showed no statisticaly significant results. Patient satisfaction with aesthetics was higher in the
LALPF group than in the LPF group (p < 0.041). Patient-based aesthetic results were also compatible with
the clinical measurements indicated by RES values (p < 0.001) (Table 4).
Discussion
The null hypothesis, that there would be no differences in clinical and aesthetic parameters between
LALPF and conventional LPF for the treatment of gingival recession defects, was rejected. The results of
the study showed significantly better outcomes in the LALPF group for GRD, CAL, and KTW. In the
literature, the reported mean percentage of root coverage ranges between 34% and 82% for LPF
procedures.6,7,9,10,36–41 Only one study reported data on the percentage of CRC, and showed CRC
percentages between 40% and 50%.42 In the present study, CRC was 81.2% for the LALPF group, which is
higher than in most previous studies.6,7,9,10,36–41 This finding can be explained by the decrease in the
flap tension and by some advantages of laser use.
Flap tension has been reported as a key factor in the surgical treatment of gingival recessions.17,43,44
Pini Prato et al.17 have reported that higher flap tensions (4–11 g) before suturing were associated with
lower recession reduction whereas minimal tensions (0–4 g) were often associated with CRC.17 Rotated
flap procedures, especially LPF, could increase the flap tension, which might jeopardize the initial wound
healing and result in less favorable results. The external vestibular laser incison used in this study was
more advantageous, probably because this technique allowed a more passive and completely relaxed
flap than the conventional LPF. Flap tension caused by movement of the lips and buccal mucosa was
relieved nontraumatically by the laser in the test group. Another benefit of the external vestibular
incison was the maximum enhancement and augmentation of the donor tissue by decreasing the apical
pull. The use of laser enabled precise vestibular deepening incisions, which freed the pedicle flap,
allowing the clinician to maneuver the tissue more properly. The increase in the amount of advancement
or mobilization of the pedicle flap (without tension) is directly related to the clinical success. The surgical
procedure reported here also provided the maximum lateral and coronal positionings of the flap; these
positionings were reported previously as one of the key factors for CRC.18,32,44
Butler has used a similar vestibular releasing incison with a scalpel during gingival recession treatment,
and reported significant postoperative ecchymosis and edema related to this incison.45 In contrast, none
of the patients in our test group had similar complaints, probably because of the advantages of lasers.
Soft tissue surgery is one of the major indications for lasers. Laser surgery can be superior to
conventional blade surgery because ablation, decontamination, and hemostasis are easier to achieve,
and there is potentially less operative and postoperative pain. However, possible damaging thermal
effects to the underlying tissues should be kept in mind when using lasers deep in the tissues. It is well
documented that the scattering of laser energy within the surrounding tissues is low, and the layer of
heat-altered tissue that remains after vaporization is relatively shallow.46
As diode lasers have an excellent soft tissue ablation capacity, a precise and nontraumatic deepithelization was performed by the laser in the test group. An attempt was made to completely remove
the epithelium, while retaining as much of the lamina propria as possible, which is more difficult to do
with scalpel. In addition, the laser-assisted technique used here may shorten the duration of treatment
by enabling three operations such as LPF, frenectomy, and vestibuloplasty in single session.
Other advantages of the use of a diode laser include a relatively bloodless operative and postoperative
field, less traumatic operation, greater accuracy in making incisions (especially for vestibular deepening
and frenectomy operations), sterilization of the surgical field, minimal swelling and scarring,
vaporization, and cutting with much less postoperative pain. This could provide potential advantages for
the surgery, the healing process, and the patients' perceptions of the procedure. The surgery can be less
invasive, take less time, and be less demanding; the healing process could be favored by the improved
wound stability of minimally mobilized flaps; and the patients could benefit from a procedure with
potentially reduced intra- and postoperative morbidity. Lasers have also been known to stimulate
growth factors, which enhances the activation of human gingival fibroblasts and periodontal ligament
cells to proliferate and release growth factors in tissues; therefore, this may have also had an impact on
our positive findings for the laser therapy.47
Kerner et al. reported that aesthetics was the main reason for the root coverage procedures, whereas
root sensitivity and soft tissue augmentation accounted for only 27.35% and 10.81%, respectively.33
CRC, good color blending of the treated area, irregular tissue texture, or inadequate contiguity with
adjacent soft tissues may affect the aesthetic perception of treatment.31,48,49 In addition, Kerner et al.
reported that soft tissue appearance is more important than the quantitative level of root coverage, and
that the colorimetric integration is the most important parameter when dealing with aesthetics.49 The
patients treated with LALPF technique were more satisfied aesthetically than the patients treated with
LPF. Another evaluation was performed by using the RES to investigate the aesthetic outcomes according
to MTC, STT, MGJ alignment and GC. The findings of this evaluation were in accordance with the patientcentered assessment results, which showed that the patients treated with LALPF had better RES scores
than did the LPF group.
Limitations
The present study has some limitations. The first one is inherent to the follow-up period. As this is a
short-term assessment of the comparison of LALPF with LPF, the evaluation period used in this study was
6 months from the last surgical treatment. Although this period is considered adequate to provide soft
tissue maturity and stability as reported in systematic reviews dealing with root coverage
procedures,50,51 it was shown that the length of follow-up is a positive predictive factor in terms of
aesthetics, and that the follow-up period should not be <12 months.49 Although diode laser does have
advantages in the management of LPF operation, the long-term benefits of its use in mucogingival
procedures need to be established. Further work in this area is required to assess whether these initial
positive results are modified over time. Another limitation is inherent to the sample size. As the inclusion
criteria of the patients were strict and it was hard to find a sufficient number of patients with isolated
gingival recession, this study was only able to include the minimal sample size.
Conclusions
In conclusion, this randomized controlled clinical trial showed that the use of a diode laser for
performing/creating an additional vestibular releasing incision during LPF had positive effects on clinical
and aesthetic outcomes in treating isolated gingival recessions. Although diode lasers may have some
advantages in the management of LPF operation, the long-term benefits of its use in mucogingival
procedures need to be established. Further work in this area is required to assess whether these initial
positive results are modified with time.